WebsocketMismatch

[hansehe]

New version of Flask (>1.1.4) does not work with Flask-Sockets (websockets).

Replicate bug by running server and client.

requirements:

Flask==2.0.2
Flask-Sockets==0.2.1
Werkzeug==2.0.2
gevent==21.8.0
websocket-client==1.2.1

flash_ws_server.py:

from flask import Flask
from flask_sockets import Sockets


app = Flask(__name__)
sockets = Sockets(app)


@sockets.route('/mixed_ws_path')
def echo_socket(ws):
    while not ws.closed:
        message = ws.receive()
        ws.send(message)


@app.route('/mixed_ws_path')
def hello():
    return 'Hello World!'


if __name__ == "__main__":
    from gevent import pywsgi
    from geventwebsocket.handler import WebSocketHandler
    server = pywsgi.WSGIServer(('', 5000), app, handler_class=WebSocketHandler)
    server.serve_forever()

flask_ws_client.py:

import websocket
import _thread
import time


def on_message(ws, message):
    print(message)


def on_error(ws, error):
    print(error)


def on_close(ws, close_status_code, close_msg):
    print("### closed ###")


def on_open(ws):
    def run(*args):
        for i in range(3):
            time.sleep(1)
            ws.send("Hello %d" % i)
        time.sleep(1)
        ws.close()
        print("thread terminating...")
    _thread.start_new_thread(run, ())


if __name__ == "__main__":
    websocket.enableTrace(True)
    ws = websocket.WebSocketApp("ws://localhost:5000/mixed_ws_path",
                                on_open=on_open,
                                on_message=on_message,
                                on_error=on_error,
                                on_close=on_close)

    ws.run_forever()

The server responds with this exception:

Traceback (most recent call last):
  File "C:\Users\heh\AppData\Local\Programs\Python\Python39\lib\site-packages\gevent\pywsgi.py", line 999, in handle_one_response
    self.run_application()
  File "C:\Users\heh\AppData\Local\Programs\Python\Python39\lib\site-packages\geventwebsocket\handler.py", line 75, in run_application
    self.run_websocket()
  File "C:\Users\heh\AppData\Local\Programs\Python\Python39\lib\site-packages\geventwebsocket\handler.py", line 52, in run_websocket
    list(self.application(self.environ, lambda s, h, e=None: []))
  File "C:\Users\heh\AppData\Local\Programs\Python\Python39\lib\site-packages\flask\app.py", line 2091, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\Users\heh\AppData\Local\Programs\Python\Python39\lib\site-packages\flask_sockets.py", line 40, in __call__
    handler, values = adapter.match()
  File "C:\Users\heh\AppData\Local\Programs\Python\Python39\lib\site-packages\werkzeug\routing.py", line 2039, in match
    raise WebsocketMismatch()
werkzeug.routing.WebsocketMismatch: 400 Bad Request: The browser (or proxy) sent a request that this server could not understand.
2021-10-08T09:59:35Z {'REMOTE_ADDR': '::1', 'REMOTE_PORT': '56214', 'HTTP_HOST': 'localhost:5000', (hidden keys: 24)} failed with WebsocketMismatch

Everything works fine with Flask version ==1.1.4

Environment:

• Python version: 3.9.0
• Flask version: 2.0.2

[ThiefMaster]

Sounds more like something to report on the flask-sockets repo to me...

Edit: https://github.com/heroku-python/flask-sockets looks pretty dead to me so you may want to look for an alternative..
And someone already reported this in heroku-python/flask-sockets#81

[hansehe]

Ok thanks! Too bad nobody looks after it.
I found a temporary solution though:
heroku-python/flask-sockets#82 (comment)